US Republicans are deploying a $100m election spending machine to savage Barack Obama's green agenda, with Karl Rove's political action committee releasing a new advert attacking the administration for funding a collapsed solar panel company.

The latest ad buy this week raises Republican spending on adverts attacking Obama's support for Solyndra to more than $9m (£5.7m), with the election still nine months away.

Republicans hope to frame the election in November as a choice between the environment and jobs. Obama, for his part, has offered a mixed response to the attacks, highlighting his energy strategy and taking out his own ads on Solyndra.

Last week Obama made a pitch for clean energy investment during his state of the union address, and on Wednesday the interior secretary, Ken Salazar, announced the development of four new areas for offshore windfarms along the mid-Atlantic coast.

Salazar said the initiative would clear the way for developing offshore windfarms in Maryland, Virginia, New Jersey and Delaware. "The federal government is now fast-tracking forward," said Maryland's Democrat governor, Martin O'Malley.

To date the main exhibits for the Republicans' new election strategy are ad buys from Rove's Crossroads GPS political action committee, including $500,000 this week, and a bigger barrage from Americans for Prosperity, which is tied to the billionaire Koch brothers. Between them, the two groups raised $100m last year.

Since late last year, Americans for Prosperity has spent $8.4m on television ads in battleground states such as Michigan and Ohio, attacking the collapse of Solyndra into bankruptcy as "Obama's green giveaway".

Republican presidential candidates have also criticised Obama for rejecting the Keystone tar sands pipeline, with the frontrunner, Mitt Romney, accusing the president of "crony capitalism".

In this week's 35-second ad from Rove's Pac, Obama is accused of using government funds to reward campaign donors. "He gave his political backers billions, a big government fiasco infused with politics at every level," a female narrator says. "Laid-off worker: forgotten. Typical Washington. Tell President Obama we need jobs not more inside deals."

Republicans in the House of Representatives have spent months investigating loan guarantees given to Solyndra, subpoenaing the White House to turn over tens of thousands of pages of documents.

They have uncovered no evidence of corruption to date. However, Obama has been hurt by the release of emails from officials expressing doubts about Solyndra's financial health before the loan.

Crossroads hopes to pick up on that unease in its ad campaign, according to a strategy memo from the Pac's president, Steven Law. "Advocates on the centre-right need to engage that debate in both moral and economic terms, showing that Obama's Washington is an unfair place, and less of Obama's invasive, free-spending and chronically politicised government is the solution," Law said in the memo.

There are signs that the Obama camp is concerned. His re-election campaign put out its first television ad last week, responding to the attacks on Solyndra.